Week 1 Stress Concentration on a Plate with hole
Week 1 Challenge: Stress concentration on the Plate with a hole
Course: Structural Analysis Using Ansys Workbench
Submitted by: Amanpreet Singh Whan
Supervisor: Vineet G
February 18, 2022
List of Figures
Figure 1- Ansys Static Structural Analysis System Workflow.
Figure 2- 2D Sketch of Plate with a Hole CAD Model.
Figure 3- Plate with a Hole final CAD Model.
Figure 4- Meshed Plate with a Hole CAD Model.
Figure 5- Plate with three Holes 2D and 3D CAD Model.
Figure 6-Meshed Plate with three Holes Model.
Figure 7- Steps followed to assign a Fixed Support Boundary Constraint.
Figure 8-Steps followed to assign a Load of 500 N.
Figure 9-Fixed Support Boundary Constraint applied to the Plate Model with three holes.
Figure 10-Force of value 500 N applied to the Plate Model with three holes.
Figure 11- Procedure to be followed to calculate results.
Table of Contents
3.1 Designing and Meshing of CAD Models.
1 Introduction
ANSYS is a general-purpose, finite-element modelling package for numerically solving a wide variety of mechanical problems. These problems include static/dynamic, structural analysis, heat transfer, and fluid problems, as well as acoustic and electromagnetic problems. There are two methods to use ANSYS. One method is to use the graphical user interface (GUI). This method follows the conventions of popular Windows and X-Windows-based programs. Another method is to use command files. The command-file approach has a steeper learning curve for many, but it has the advantage that the entire analysis can be described in a small text file, typically in less than 50 lines of commands. This approach enables easy model modifications and minimal file-space requirements. The ANSYS environment contains two windows: the main window and an output window. A large number of files are created when ANSYS simulation is run.
2 Aims
- Design a Plate with a Hole and a Plate with three Holes CAD models as per the given specifications of the challenge.
- Apply Boundary Conditions and simulate both the designed CAD models.
- Determine Total Deformation and Maximum Stress results for the performed simulations and compare the results for the same.
3 Methodology and Results
The section describes the different stages that were performed using an engineering tool Ansys Workbench 2022 for the completion of the Week 1 Challenge. These stages can be further broadly sub-categorised into three key steps, starting from designing of cad model to applying the boundary conditions and finally performing the simulation to obtain the desired results.
3.1 Designing and Meshing of CAD Models
After opening the Ansys Workbench, the first step is to select the Analysis type and then define appropriate material from the Engineering Data option for the designed CAD model. The Static Structural and Structural Steel was selected for System Analysis type and material respectively. The CAD models were created using the SpaceClaim Geometry CAD tool.
After updating the created model in the Ansys Workbench, the next step is to generate a good quality mesh. Meshing is a phase where the CAD geometry is discretised to represent the computational domain in which the solver will discover a solution. A refined mesh helps to achieve better results. The tetrahedral mesh with an element size of 3.5 mm was generated for the plate with a hole CAD model.
The Plate with three Holes was created adopting the above-mentioned procedure. The final CAD design and meshed model are presented in the following figures.
3.2 Boundary Conditions
Boundary conditions are constraints necessary for the solution of a boundary value problem. The Fixed support constraint restricts all the translation degrees of freedom over the assigned entities to be zero. The force boundary condition applies a distributed force to the structure. It can be assigned to any number of faces of a structure. This boundary condition works as surface traction on each element of the assigned topological entity and its value is proportional to each element’s area.
Two Boundary constraints, Fixed Support and Force (directional) are assigned to two opposite respective faces of the plate as per challenge requirements. The process followed to assign both the boundary constraints are presented in the following figures.
Case 1: Plate with a hole
Case 2: Plate with three holes
Simulation Results
To visualise the simulation or results, the desired output cards have to be created. Total Deformation, Equivalent Elastic Strain and Equivalent Stress (Von Mises Stress) cards were created using the procedure illustrated in the following picture. It must be noted that the results have to be generated by running the solve command.
Case 1: Plate with a hole Simulation Results
Case 2: Plate with three holes Simulation Results
4 Conclusion
In conclusion, the main aim of the Week 1 challenge Design a Plate with a Hole and a Plate with three Holes CAD models, apply Boundary Constraints and run the simulation and compare the obtained results for the same.
It was found that the total deformation in case 2 is slightly more in comparison to case1. However, the stresses and strains generated in case 1 are higher in comparison to case2. Considering the above aspects, it would not be wrong to say that the Plate with three holes should be selected in place of the Plate with a single hole since it has resulted in better stress-strain contours when a directional load is assigned to it.
However, when it comes to production, the Plate with a hole CAD Design should be considered because creating a Plate with three holes would necessitate additional CNC work, which would not only affect but also raise the cost of manufacturing.